Each document, reference, patent application or patent cited in this text is expressly incorporated herein in their entirety by reference, which means that it should be read and considered by the reader as part of this text. That the document, reference, patent application, or patent cited in this text is not repeated in this text is merely for reasons of conciseness.
The following discussion of the background to the invention is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge of the person skilled in the art in any jurisdiction as at the priority date of the invention.
Fox predation of native species is a serious problem in Australia, and south Western Australia in particular. Whilst it is known that the removal of foxes leads to increased numbers of native animals, their specific predation habits are largely unknown. Current methods of studying their predatory behaviour have typically involved direct observation, or evidence gathering. This has been somewhat problematic as, foxes being nocturnal, predation generally occurs during darkness. Furthermore, these animals often inhabit rough and inaccessible terrain, and may discover prey at any location within a wide area. The positive identification of individual animals has also proven difficult.
Ultra High Frequency (“UHF”) Radio Frequency Identification (“RFID”) devices have been used to monitor and track the presence of objects. Between 13 MHz and 2.4 GHz, many countries (including USA and Australia) have allocated space for unlicensed Industrial Scientific and Medical (“ISM”) use, at 915 MHz and 433 MHz. Many commercial RFID systems employ the 915 MHz band, but experience has shown that signals at this frequency are subject to absorption by water, and may be particularly vulnerable to antenna de-tuning effects when placed in close proximity to water (including living biological tissue) or metal.
No RFID tag has the ability to monitor whether an animal in close proximity to the tag is alive or dead in addition to being activated exclusively by close range (less than 50 cm) transmissions whilst retaining the ability to transmit identification numbers and other data over a greater distance.
Many passive RFID tags are small enough and light enough to be placed on a small animal such as a field mouse. However, all prior art systems that the applicant is aware of are, at best, bi-directional in nature; requiring an interrogating unit to be in certain positions related to the tag in order that effective data transferral may take place.